Actually, botting is not only 100% possible, it is still widely used. They are used for "big" things (like claiming HNM mobs), as well as "small" things (like fish bot). And yes, fish botting still exists.
Only way to get rid of it is to get rid of the vulnerabilities which allows programs like Windower to work. Somehow I doubt many are willing to give up their windower just to get rid of some pesky ol botters.